Low level acts of aggression in school are associated with a host of emotional arousal, social problem-solving, peer relationship, and academic difficulties. School-wide interventions may decrease aggressive interactions and promote cooperative play and social skills among students. In the current study, the authors used a participatory-action research model to co-construct a playground-based recess program in a relatively large urban elementary school. The manuscript illustrates the partnership process and how data was used to inform intervention implementation procedures. The role of psychologists working at the whole-school level is highlighted.